Endospores of Bacillus spp., especially Bacillus subtilis, have served as experimental models for exploring the molecular mechanisms underlying the incredible longevity of spores and their resistance to environmental insults. In this review we summarize the molecular laboratory model of spore resistance mechanisms and attempt to use the model as a basis for exploration of the resistance of spores to environmental extremes both on Earth and during postulated interplanetary transfer through space as a result of natural impact processes.

/pdf/resistance-of-bacillus-endospores-to-extreme-terrestrial-and-2qp3zxqicl.pdf

Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments.

Physical Processes in the Interstellar Medium

Various present and future specialized applications of magnets require monodisperse, small magnetic particles, and the discovery of molecules that can function as nanoscale magnets was an important development in this regard. These molecules act as single-domain magnetic particles that, below their blocking temperature, exhibit magnetization hysteresis, a classical property of macroscopic magnets. Such 'single-molecule magnets' (SMMs) straddle the interface between classical and quantum mechanical behaviour because they also display quantum tunnelling of magnetization and quantum phase interference. Quantum tunnelling of magnetization can be advantageous for some potential applications of SMMs, for example, in providing the quantum superposition of states required for quantum computing. However, it is a disadvantage in other applications, such as information storage, where it would lead to information loss. Thus it is important to both understand and control the quantum properties of SMMs. Here we report a supramolecular SMM dimer in which antiferromagnetic coupling between the two components results in quantum behaviour different from that of the individual SMMs. Our experimental observations and theoretical analysis suggest a means of tuning the quantum tunnelling of magnetization in SMMs. This system may also prove useful for studying quantum tunnelling of relevance to mesoscopic antiferromagnets.

Exchange-biased quantum tunnelling in a supramolecular dimer of single-molecule magnets

Amino acids are the essential molecular components of living organisms on Earth, but the proposed mechanisms for their spontaneous generation have been unable to account for their presence in Earth's early history1. The delivery of extraterrestrial organic compounds has been proposed as an alternative to generation on Earth2,3,4,5, and some amino acids have been found in several meteorites6,7,8,9. Here we report the detection of amino acids in the room-temperature residue of an interstellar ice analogue that was ultraviolet-irradiated in a high vacuum at 12 K. We identified 16 amino acids; the chiral ones showed enantiomeric separation. Some of the identified amino acids are also found in meteorites. Our results demonstrate that the spontaneous generation of amino acids in the interstellar medium is possible, supporting the suggestion that prebiotic molecules could have been delivered to the early Earth by cometary dust, meteorites or interplanetary dust particles.

Amino acids from ultraviolet irradiation of interstellar ice analogues.

t. Chirality and Chiral Homogeneity in Nature 2. Biotic Theories 3. Abiotic Theories 3.1. Chance Mechanisms 3.1.1. Models for Spontaneous Symmetry Breaking 3.1.2. Spontaneous Resolution on Crystallization 3.1.3.Asymmetric Syntheses in Chiral Crystals 3.1.4. Asymmetric Adsorption and Catalysis on Quartz 3.1.5.Asymmetric Adsorption and Polymerization on Clays 3.1.6. Conclusions 3.2. Determinate Mechanisms 3.2.1. Regional and/or Temporal Processes 3.2.1.1.Electric, Magnetic and Gravitational Fields 3.2.1.2.Circularly Polarized Eight 3.2.1.2.1.Asymmetric Photoequilibration 3.2.1.2.2.Photochemical Asymmetric Synthesis 3.2.1.2.3.Asymmetric Photolysis 3.2.1.2.4.Sources of Circularly Polarized Eight 3.2.2. Universal Processes 3.2.2.l.The Violation of Parity 3.2.2.2.The Vester-Ulbricht (V-U) ttypothesis 3.2.2.3.Radioracemization 3.2.2.4.Direct Effects of Chiral Particles 3.2.2.4.1 .Electrons 3.2.2.4.2.Protons 3.2.2.4.3.Positrons and Muons 3.2.2.5.Weak Interactions, Neutral Currents and Parity Violating Energy Differences 3.2.3. Conclusions 4. The Amplification of Enantiomeric Excesses

The origin and amplification of biomolecular chirality

https://scholarlypublications.universiteitleiden.nl/access/item%3A2727940/view

Chemical and biological evolution in space

For the first time a laboratory simulation of the effect of the interstellar environment has been used to provide quantitative estimates of bacterial spore survival in the space between the stars. In the diffuse regions between clouds ten percent survival is limited to at most hundreds of years although one in ten thousand may survive for several thousand years. Within common dense clouds the ten percent life expectancy is extended to tens of millions of years because of the severely reduced ultraviolet within these clouds as well as because of the accretion of ultraviolet absorbing mantles on the spores. The random motion of molecular clouds is shown to provide a possible vehicle for transport of spores from one solar system to another. The most hazardous times in such a journey are at the start and finish and, although the requirements for survival during these periods are quantified here, the possibility or probability of their being satisfied remains pure conjecture.

Panspermia — a Modern Astrophysical and Biological Approach

Experimental evidence is presented for the effects of very low temperature and UV radiation, characteristic of the interstellar medium, on the survival of bacteria. In the most general space environment, 10 percent survival times are only of the order of hundreds of years, too short for panspermia to work. In a substantial fraction of space within dark clouds, however, it is shown that, even with conservative figures, survival times as long as millions to tens of millions of years are attainable. In such conditions, clouds could transport organisms from one solar system to another in times significantly shorter than the mean survival time. This occurs with significant probability.

Can spores survive in interstellar space

Microorganisms and biomolecules in space environment experiment ES 029 on spacelab-1

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Chemical and biological evolution in space

Panspermia — a Modern Astrophysical and Biological Approach

Can spores survive in interstellar space

Microorganisms and biomolecules in space environment experiment ES 029 on spacelab-1